This invention relates to an extrusion forging method particularly suitable for extrusion forging long products.
The extrusion forging method generally comprises placing a billet in a container and exerting pressure on the billet as held in the container with a punch, for example, thereby extruding the billet through a die. Since this method can be easily performed even on billets of hard metal, it has come to find extensive utility in the fabrication of various parts including automobile parts. Heretofore, the extrusion forging method has been mainly utilized for the fabrication of relatively short rods of circular and complex sections. The reason for the small length of the products is that the production of long rods not merely necessitates application of high pressure during the extrusion forging but also entails a possibility that the fabricated products, when being removed from the die, will be malformed and accordingly lacking in dimensional precision.